A filter blocking access to .info top-level domains for senators and departmental staff has been lifted, following complaints from Greens communications spokesperson Scott Ludlam.

It was revealed earlier this month that the block of all .info top-level domains was enacted within the halls of parliament and its offices on the basis of advice from the Defence Signals Directorate (DSD). According to the Department of Parliamentary Services acting secretary David Kenny, a total of 35 million websites, including the .info sites, are filtered from view within the parliament.

In estimates hearings, Ludlam asked Kenny whether the block could be reviewed, telling the acting secretary that it had prevented him from viewing anti-war and peak oil websites. The department confirmed to ZDNet Australia this afternoon that following Ludlam's request, the block on .info sites has been removed.

At the time, Ludlam said that it was particularly ironic for Greens MPs, who are opposed to Labor's controversial mandatory internet service provider-level internet filter, to be subject to such a wide-spanning filter themselves.

"I spent two years campaigning against an internet filter for the general population, only to discover that now I am one of the only people in the country who is filtered, which is a little bit alarming," he said.

In a press conference yesterday, Communications Minister Stephen Conroy was asked about the status of the government's plan to introduce legislation to support its mandatory internet filter, which would be based on a blacklist managed by the Australian Communications and Media Authority (ACMA).

In his response, Conroy referred to the voluntary Interpol filter implemented by Telstra, Optus and Primus, leading to reports from AAP that Telstra and Optus had implemented the mandatory internet filter.

"Well, two companies, in fact three companies, have already introduced it. It may come as a great surprise to you that the internet hasn't slowed down or collapsed," Conroy said of the voluntary filter, adding that this showed that filters do not reduce internet speeds for consumers.

"They're testing it against the Interpol list, and overwhelmingly Australians have not noticed any difference, any difference whatsoever. We've seen announcements by a whole range of other companies that they're going to introduce it themselves voluntarily. We welcome this; we think this is a fantastic step forward. I've been calling on the sector to stand up and move forward. I think I've only seen now one company that has indicated it may not introduce voluntarily the filter."

The government has previously indicated that legislation for the mandatory internet filter will be introduced once the Australian Law Reform Commission's (ALRC) recommendations on what content should be classed as "refused classification" has been considered by the government.